A Comprehensive Analysis of LYAR in Colorectal Cancer: Prognostic Marker and Therapeutic Target

<b><i>Background:</i></b> Colorectal cancer (CRC) is a major global health challenge with a need for new biomarkers and therapeutic targets. This work investigated the biological mechanisms and clinical value of Ly1 antibody reactive (LYAR) in CRC. <b><i>Methods:</i></b> We analyzed LYAR mRNA expression across multiple public databases, including genotype-tissue expression, gene expression omnibus, Oncomine, and the cancer genome atlas, alongside in-house immunohistochemical data to evaluate LYAR protein expression in CRC and non-CRC colorectal tissues. Gene set enrichment analysis (GSEA) was used to elucidate LYAR's biological functions, and its impact on the tumor immune microenvironment was assessed using CIBERSORT, ESTIMATE, and single-cell RNA sequencing techniques. In addition, LYAR's association with clinicopathological features and patient prognosis was explored, and its influence on drug sensitivity was investigated using the Connectivity Map database. <b><i>Results:</i></b> LYAR was significantly upregulated in CRC tissues compared with non-CRC colorectal counterparts, associated with altered immune cell composition and enhanced RNA processing, splicing, and cell cycle regulation. High LYAR expression correlated with poor disease-free and overall survival, underscoring its prognostic value. GSEA revealed LYAR's involvement in critical cellular processes and pathways, including DNA repair, cell cycle, and mTORC1 signaling. Correlation analysis identified genes positively and negatively associated with LYAR, leading to the discovery of temsirolimus and WYE-354, mTOR inhibitors, as potential therapeutic agents for CRC. Furthermore, LYAR expression predicted increased sensitivity to cetuximab in RAS wild-type metastatic CRC, indicating its utility as a biomarker for treatment responsiveness. <b><i>Conclusions:</i></b> LYAR's upregulation in CRC highlights its potential as a biomarker for prognosis and therapeutic targeting, offering insights into CRC pathology and suggesting new avenues for treatment optimization.